Connecting device for pipings, pipes and conduits

ABSTRACT

A crimping connection comprising an unthreaded sleeve having a tail section joined to a head section. The tail section includes a malleable portion which is adapted to be crimped onto the outer periphery of a pipe and the head section includes a portion of higher hardness than the malleable portion which is adapted to be removably attached within a pipe.

This application is a continuation of application Ser. No. 433,128,filed 9-28-82, now abandoned.

Connecting systems in the field of pipings, pipes and conduits areknown, consisting substantially of a connection in form of a sleeveserving to connect two pipe portions brought into alignment with oneanother. The sleeve is applied onto both facing pipe ends by means of acrimping tool. In this way, zones of the sleeve provided on the outsideof the sleeve are radially crimped into the pipe ends by tool diesthereby obtaining a permanent metal to metal joint.

A connection of this type for proper functioning must have an elasticlimit lower than that of the pipes to which it is crimped on.

Dismountable connecting devices implemented on fluid conduits comprisinga nut (1) are also known. A connecting device of this type sometimesrequires high tightening torques to provide proper sealing, under severeoperative conditions (for example, high pressure, vibrations, thermaldilation, and so on), thereby leading to the selection of minimallydeformable and, therefore, hard materials for the various constitutiveelements of such device.

The sealing of those connecting devices is generally ensured by thecontacting of a spherical, toroidal or conical male element (2) within aconical female element (3), the most currently used angles being 24°,45°, 60°, 80°, 90°, (refer to FIG. 1 of the attached drawings).

The present invention is intended for providing a connecting devicecapable of fulfilling both the role of a malleable crimping connectionand the role of a dismountable male connecting device.

However, for realizing a device of this type, one has to meet with anincompatibility caused by the fact that the hardness required fordismountable connecting is too high for the malleable connection, orthat malleability required for the malleable connection leads to toohigh a deformation of the dismountable connection.

The present invention conciliates the required hardness and the requiredmalleability by developing in a zone of an unthreaded connection sleevean adventitious portion of a different nature, harder when suchadventitious portion is intended for realizing a dismountable connectingmale portion (the other connection portion then remaining a malleablecrimping portion); more malleable when such adventitious portion isintended for realizing a crimping connection portion (the otherconnection portion remaining a dismountable hard connecting portion),hence two possible simultaneous functions, of dimountable connecting andof crimped connection, for one and the same accessory according to theinvention.

According to the invention it is intended to develop such a harderadventitious portion on the malleable accessory, at the beginning byseveral processes, either metallurgical or mechanical processes.

According to one mode of manufacturing, the harder adventitious portionis produced by localized machining hardening.

According to another mode of realization the harder adventitious portionis produced by adding a part thereto such that the malleable sleeve mayform a continuous assembly with the added member.

According to the invention, it is intended to develop such a moremalleable adventitious portion, on the accessory, which is hard at thebeginning, through localized overquenching, which lowers the elasticlimit in the zone of the accessory which is then considered.

Other characteristics and advantages of the present invention willappear from the following description which is made with reference tothe attached drawings on which:

FIG. 1 represents a cross-section through a dismountable connectingdevice with a nut of the known type;

FIG. 2 represents in a half-cross-sectional view an accessory accordingto the invention to show a malleable portion as required for the crimpedconnecting and a harder adventitious portion as required for theintended dismountable connecting;

FIG. 3 is a half cross-sectional view of an accessory according to theinvention in which a hard adventitious portion is associated with amalleable crimping portion;

FIG. 4 is a half cross-sectional view of an accessory according to theinvention which is made by assembling a hard portion and a malleableportion;

FIG. 5 is a half cross-sectional view in which an added portionconstitutes the hard portion of the accessory according to theinvention;

FIG. 6 is a half cross-sectional view of an accessory according to theinvention which comprises a hard reinforcing means;

FIG. 7 is a half cross-sectional view of an accessory according to theinvention which is mechanically machined to obtain a dismountablehardened connecting portion; and

FIG. 8 is a half cross-sectional view of an accessory according to theinvention which is electrolytically treated with a view to obtaining adismountable hardened connecting portion.

There is shown in FIG. 2 an accessory (4) according to the invention,comprising a malleable crimping portion (5) in a tail section of thesleeve and a harder dismountable adventitious connecting portion (6) ina head portion of the sleeve, note that the head section has a largerdiameter than the tail section.

According to one aspect of the invention, it is intended to make up theaccessory by the assembly of two complete parts with one constitutingthe dismountable connecting portion of a hard material and the other themalleable crimping portion.

The hard material may be a steel of the stainless type structurallyhardened in the aged condition (for example, Z6NCT25), and the malleablematerial may be a steel of the stainless type, austenitic in theoverquenched condition (for example, AISI 316L).

The technologies resorted to by the invention for assembling these twoparts together do not modify the characteristics of the materials athand or can only modify them very locally.

In the form of embodiment in FIG. 3 the portion or part of hard material(6A) is assembled along a line (5) to the portion or part of malleablematerial (5A) through an operation of end to end welding throughelectronic bombardment.

In the form of embodiment shown in FIG. 4, the assembly of a completeportion or part of hard material (6B) to a complete portion or part ofmalleable material (5B) is produced through the assembling thereof bybrazing, glueing, hooping or any other operation to permit the bondingtogether of both parts, the hooping being produced, e.g. through pressassembling or thermally.

For the realization of a suitable assembly both portion (6B) and portion(5B) are formed with complementary assembling collars (7 and 8).

In the form of embodiment shown in FIG. 5 the added portion or part ofhard material is limited to a reamed spherical segment (6C) which formsby its lateral convex surface (9) the required sealing zone for therealization of a dismountable connecting.

The segment (6C) is received in an annular groove (10) outwardly formedin the malleable portion or part (5C) which extends thereto.

It is considered according to the invention to provide the assembly ofportions (6C) and (5C) by end to end welding through electronicbombardment; by brazing, glueing, hooping or any other operation topermit the bonding together of both parts.

In the form of embodiment shown in FIG. 6 a simple inner reinforcingmeans in form of a ring (6D) of a hard material limits deformation of asealing zone (11) made integrally with the malleable crimping portion(5D) which extends thereto. Such reinforcing ring can be assembledaccording to the invention by welding through electronic bombardment,brazing, glueing, hooping or any other operation to permit the bondingof both parts together.

The reinforcing ring (6D) is received in an annular groove (12) inwardlyprovided in the malleable portion of part (5D).

In the form of embodiment shown in FIG. 7 the accessory according to theinvention is entirely machined from a malleable material which may be316L. The sealing zone (13) of the dismountable connection is obtainedby hardening such zone through cold working by rollers. The malleablecrimping portion (5E) therefore extends up to under such hardenedsealing zone (13).

In the form of embodiment shown in FIG. 8 the accessory in accordancewith the invention is also entirely machined from overquenched 316L orsimilar material, the hardening of a sealing zone (14) of dismountableconnecting being obtained by electrolytic deposition (hard chromiumplating), the malleable crimping portion (5F) therefore extends here tooup to under the hard sealing zone (14).

It is also considered according to the invention to combine theabove-described solutions and for example the outer cold working (FIG.7) and the inner reinforcing (FIG. 6).

In a first step the accessory can be entirely machined from a stainlesssteel of the structural hardening type (for example, Z6NCT25) previouslyaged to confer maximum hardness. The accessory is thereafter submittedto overquenching through high frequency induction, localized to portion(5).

In the case of Z6NCT25 such overquenching lowers the elastic limit to0.2% (RO, 2) from about 750 MPa to about 250 MPa.

After treatment the accessory comprises the malleable crimping portion(5) and the harder dismountable connecting portion (6).

It must be noted that the hard adventitious portion (6, 6A, 6B, 9, 11,13, 14) whatever be its mode of manufacture is always configured so asto realize a spherical, toroidal or conical male member, of dismountableconnecting device and that the malleable portion of crimping connection(5, 5A, 5B, 5C, 5D, 5E, 5F) comprises at least one zone (16) intendedfor being radially crimped into the pipe end, and means for preventingrotation of the connection with respect to the pipe on which it isdefinitely crimped. The means for preventing rotation of the connectionmay consists of flat portions (15) or else, an inner rib which can be ahelical rib.

The accessory according to the invention is applied more particularly tothe aeronautic field but can also be applied to other fields such as forexample vessels or offshore platforms.

Finally, it will be understood that this invention was only describedand represented in a preferred exemplifying way and that any equivalentparts can be substituted for its constitutive elements without howeverdeparting from its scope.

I claim:
 1. A crimping connecting accessory for connecting rigidpipings, comprising an unthreaded sleeve having:a tail section includinga first malleable portion for a first connection of the radial crimpingtype onto the outer periphery of an end of a first pipe; and a headsection including a second portion of higher hardness than said firstmalleable portion for a second connection of the dismountable type intoa female member attached to an outer periphery of an end of a secondpipe, said head section being of a larger diameter than said tailsection, said tail section and said head section being joined to oneanother to form a single metal piece, wherein: said first malleableportion comprises at least one zone for radial crimping onto an endpiping and means for preventing said malleable portion from rotatingwith respect to said pipe on which it is crimped.
 2. A crimpingconnecting accessory for connecting rigid pipings, comprising anunthreaded sleeve having:a tail section including a first malleableportion for a first connection of the radial crimping type onto theouter periphery of an end of a first pipe; and a head section includinga second portion of higher hardness than said first malleable portionfor a second connection of the dismountable type into a female memberattached to an outer periphery of an end of a second pipe, said headsection being of a larger diameter than said tail section, said tailsection and said head section being joined to one another to form asingle metal piece, wherein: said head section defines a sealing zonehaving a second malleable portion; and said second malleable portiondefines a lateral convex surface, a member of hard material, distinctfrom said lateral concave surface, being fixed onto said lateral convexsurface of said second malleable portion.
 3. A crimping connectingaccessory for connecting rigid pipings, comprising an unthreaded sleevehaving:a tail section including a first malleable portion for a firstconnection of the radial crimping type onto the outer periphery of anend of a first pipe; and a head section including a second portion ofhigher hardness than said first malleable portion for a secondconnection of the dismountable type into a female member attached to anouter periphery of an end of a second pipe, said head section being of alarger diameter than said tail section, said tail section and said headsection being joined to one another to form a single metal piece,wherein: an annular groove is outwardly formed in said first malleableportion, a reamed spherical segment of hard material being received andfixed in said annular groove.
 4. A crimping connecting accessory forconnecting rigid pipings, comprising an unthreaded sleeve having:a tailsection including a first malleable portion for a first connection ofthe radial crimping type onto the outer periphery of an end of a firstpipe; and a head section including a second portion of higher hardnessthan said first malleable portion for second connection of thedismountable type into a female member attached to an outer periphery ofan end of a second pipe, said head section being of a larger diameterthan said tail section, said tail section and said head section beingjoined to one another to form a single metal piece, wherein: said headand said tail sections are formed with complementary assembling collars,said collars defining surfaces along which said complementary assemblingcollars are fixed to one another.
 5. A crimping connecting accessory forconnecting rigid pipings, comprising an unthreaded sleeve having:a tailsection including a first malleable portion for a first connection ofthe radial crimping type onto the outer periphery of an end of a firstpipe; and a head section including a second portion of higher hardnessthan said first malleable portion for a second connection of thedismountable type into a female member attached to an outer periphery ofan end of a second pipe, said head section being of a larger diameterthan said tail section, said tail section and said head section beingjoined to one another to form a single metal piece, wherein: said firstmalleable portion is monolithic with said second portion of higherhardness and is developed on said accessory which is originally entirelyhard.
 6. A crimping connecting accessory for connecting rigid pipings,comprising an unthreaded sleeve having:a tail section including a firstmalleable portion for a first connection of the radial crimping typeonto the outer periphery of an end of a first pipe; and a head sectionincluding a second portion of higher hardness than said first malleableportion for a second connection of the dismountable type into a femalemember attached to an outer periphery of an end of a second pipe, saidhead section being of a larger diameter than said tail section, saidtail section and said head section being joined to one another to form asingle metal piece, wherein: said first malleable portion is monolithicwith said second portion of higher hardness and is obtained on saidaccessory by localized overquenching a zone within said head section,which lowers the elastic limit in said zone of the accessory.
 7. A pipecoupling element for connecting rigid pipes, comprising:a first endportion and a second end portion, said first end portion being connectedto said second end portion and being integral therewith, said first endportion comprising a malleable material and thereby constituting meansfor forming a first connection of the radial crimping type onto an outerperiphery of an end of a first pipe, said second end portion comprisinga material having a higher hardness than said malleable material, saidsecond end portion having a male element and constituting means forproviding a second connection of the dismountable type into a femalemember attached to an outer periphery of an end of a second pipe, saidhigher hardness material imparting to said male element sufficientrigidity to prevent collapse thereof when said second end portion issubjected to use as said second connection of the dismountable type,wherein: said malleable material is monolithic with said higher hardnessmaterial and is obtained by localized overquenching.